CN1705019A - Optical disc apparatus and information playback method - Google Patents

Abstract

The optical disc device in the present invention includes an offset control unit (42) that selects parameters according to the type of optical disc and performs signal processing (offset control) using the selected parameters.

Description

Optical disc device and information reproducing method

technical field

The present invention relates to an optical disc device for reproducing information from an optical disc based on light reflected from the optical disc. The present invention also relates to an information reproducing method for reproducing information from an optical disc based on reflected light from the optical disc.

Background technique

In recent years, optical disc devices have been proposed including various reproduction signal processing techniques for accurately reproducing optical discs. For example, in Japanese Patent Application KOKAI Publication No. 2001-195830 (paragraph No. 0123, FIGS. 20, 21 and 22, loop filter 49), an optical disc device including Technology that improves the quality of the reproduced signal and improves the reproduction ability for abnormal signals through shift correction and loop filter.

However, in the above documents, the content of the loop filter (circuit for smoothing the detected offset value) of the offset controller is not disclosed. Assume that for an ordinary loop filter, the control frequency band of the loop filter is uniquely determined and cannot be changed. Thus, once a given loop filter control band of the offset controller is determined for a certain type of disc targeted, it cannot always be sufficiently suppressed when another type of disc is targeted for reproduction. Reproduce signal offset. Consequently, sufficient performance for identifying reproduced signals cannot be obtained, and thus poses a problem.

Contents of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disc device and an information reproducing method that perform reproduction with high accuracy corresponding to various types of optical discs.

In one aspect of the present invention, the optical disc device includes: a detection unit configured to detect reflected light from the optical disc; a signal processing unit configured to generate a binary signal from an analog reproduction signal based on the reflected light; and a determination unit configured to For determining the type of the optical disc based on the information indicating the type of the optical disc, the information indicating the type of the optical disc is reflected in the reflected light, wherein the signal processing unit selects one of the plurality of parameters for determining the signal processing bandwidth based on the determination result of the optical disc type. One of, and based on the selected parameters, a binary signal is generated from an analog reproduced signal.

In another aspect of the present invention, an information reproducing method includes: detecting reflected light from an optical disc; determining the type of the optical disc based on information indicating the type of the optical disc, the information indicating the type of the optical disc being reflected in the reflected light; determining the optical disc type based on As a result, one of a plurality of parameters for determining a signal processing bandwidth is selected; and based on the selected parameter, a binary signal is generated from the reflected light-based analog reproduced signal.

In the following description, other objects and advantages of the present invention will be given, and some of them will be obvious through the description, or can be understood by practice of the present invention. The objects and advantages of the invention will be realized and obtained by means of the embodiments and combinations particularly pointed out hereinafter.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, show embodiments of the invention and, together with the general description given above and the detailed description of the embodiments given below, serve to explain the invention. principle.

1 is a block diagram showing an example of a schematic configuration of a signal processing circuit according to the first embodiment;

Figure 2 is a block diagram showing an example of a schematic configuration of a bias controller;

Fig. 3 shows an example of a reproduced signal obtained from a single-layer optical disc in a situation where no offset control is applied;

4 shows an example of a reproduced signal obtained from a single-layer optical disc in the case of applying offset control;

Fig. 5 shows an example of a reproduced signal obtained from a dual-layer optical disc in the case where no offset control is applied;

FIG. 6 shows an example of a reproduced signal obtained from a dual-layer optical disc in the case of applying offset control;

7 is a block diagram showing a schematic configuration example of a signal processing circuit according to the second embodiment;

Figure 8 shows an example of the relationship between the offset control band and the SbER value on a single-layer disc;

Figure 9 shows an example of the relationship between the offset control band and the SbER value on a dual-layer disc;

10 is a block diagram showing a schematic configuration example of a signal processing circuit according to the third embodiment;

11 is a block diagram showing a schematic configuration example of a signal processing circuit according to the fourth embodiment;

12 is a block diagram showing a schematic configuration of an example of an optical disc device in the present invention;

13 is a block diagram showing a schematic configuration of another example of an optical disc device in the present invention;

14 is a flowchart for explaining signal processing according to the first embodiment; and

The flowchart of Fig. 15 is used to explain signal processing according to the second embodiment.

Detailed ways

Next, a schematic configuration of an example of an optical disc device in the present invention will be described with reference to the drawings.

Fig. 12 is a block diagram showing a schematic configuration of an example of an optical disc device in the present invention. This optical disc device records information on an optical disc D and reproduces data recorded on the optical disc D. FIG.

The optical disc D records information in the form of marks and spaces in advance. Also, on the optical disc D, a modulation code in which the shortest mark or the shortest space is set to 2T is employed. The optical disc device reproduces the information recorded on the optical disc D at a channel bit rate of 64.8 Mbps. The optical disc D as a reproduction target includes two types of optical discs. One is a so-called single-layer disc, which has one recording/reproducing layer on each side, and the other is a so-called dual-layer disc, which has two recording/reproducing layers on each side. replay layer. On single-layer and dual-layer optical discs, pieces of information indicating the type of the optical disc are recorded at predetermined positions.

As shown in FIG. 12, the optical disc device includes an optical pickup 10, a modulation circuit 21, a recording/reproduction control unit 22, a laser control circuit 23, a signal processing circuit 24, a demodulation circuit 25, an actuator 26, and a disc type determination unit. 27, and the focus tracking control unit 30.

The optical pickup 10 also includes a laser 11 , a collimator lens 12 , a polarizing beam splitter (hereinafter referred to as PBS) 13 , a quarter wave plate 14 , an objective lens 15 , a focusing lens 16 , and a photodetector 17 .

The focus tracking control circuit 30 also includes a focus error signal generation circuit 31 , a focus control circuit 32 , a tracking error signal generation circuit 33 , and a tracking control circuit 34 . Next, the operation of recording information on the optical disc D in this optical disc device will be described. The modulation circuit 21 modulates recording information (data symbols) from the host into a channel bit sequence according to a predetermined modulation method. A channel bit sequence corresponding to recording information is input to the recording/reproducing control unit 22 . Furthermore, a recording/reproducing instruction (in this case, a recording instruction) is output from the host to the recording/reproducing control unit 22 . The recording/reproducing control unit 22 outputs a control signal to the actuator 26, and drives the optical pickup so that the light beam is properly focused on the target recording position. The recording/reproducing control unit 22 also supplies the channel bit sequence to the laser control circuit 23 . The laser control circuit 23 converts the channel bit sequence into a laser driving waveform, and drives the laser 11 . That is, the laser control circuit 23 pulse-drives the laser 11 . According to this operation, the laser 11 emits a recording beam corresponding to the desired bit sequence. Through the collimating lens 12, the recording light beam emitted by the laser 11 becomes parallel light, and the light beam enters and passes through the PBS 13. The light beam passing through PBS 13 passes through quarter-wave plate 14 again, and is focused on the information recording surface of optical disc D by objective lens 15. The focus control performed by the focus control circuit 32 and the actuator 26, and the tracking control performed by the tracking control circuit 34 and the actuator 26, maintain the focused recording beam at a point where an optimum microspot can be obtained on the recording surface ( microspot) state.

Next, the operation of reproducing data from the optical disc D in this optical disc device will be described. A recording/reproducing instruction (in this case, a reproducing instruction) is output from the host to the recording/reproducing control unit 22 . The recording/reproducing control unit 22 outputs a reproduction control signal to the laser control circuit 34 in accordance with a reproduction instruction from the host computer. The laser control circuit 23 drives the laser 11 based on the reproduction control signal. According to this operation, the laser 11 emits a reproduction beam. The reproduced light beam emitted from the laser 11 is transformed into parallel light through the collimator lens 12 , and the light beam enters and passes through the PBS13. The light beam passing through PBS 13 passes through quarter-wave plate 14 again, and is focused on the information recording surface of optical disc D by objective lens 15. The focus control performed by the focus control circuit 32 and the actuator 26, and the tracking control performed by the tracking control circuit 34 and the actuator 26, keep the focused reproduction beam at an optimum beam spot on the recording surface. Note that trace control will be described in detail later. In this case, the reproducing light beam emitted onto the optical disc D is reflected by the reflective film or the reflective recording film in the information recording surface. The reflected light passes through the objective lens 15 in the opposite direction, and becomes parallel light again. The reflected light then passes through the quarter wave plate 14, has a polarization perpendicular to the incident light, and is reflected by the PBS 13. The light reflected by the PBS 13 becomes converging light through the focusing lens 16, and enters the photodetector 17. The photodetector 17 has, for example, four photodetection elements. The light beam incident on the photodetector 17 is converted into an electric signal through photoelectric conversion, and then amplified. The amplified signal is equalized and binarized by the signal processing circuit 24 and sent to the demodulation circuit 25 . The demodulation circuit 25 performs a demodulation operation corresponding to a predetermined modulation method, and outputs reproduced data.

Based on part of the electric signal output from the photodetector 17, the focus error signal generation circuit 31 generates a focus error signal. Also, based on part of the electric signal output from the photodetector 17, the tracking error signal generating circuit 33 generates a tracking error signal. Based on the focus error signal, the focus control circuit 32 controls the focus of the actuator 26 and the beam spot. Based on the tracking error signal, the tracking control circuit 34 controls the tracking of the actuator 26 and the beam spot.

The disc type determination unit 27 determines the type of the optical disc D based on the information indicating the type of the disc contained in the reproduced data. That is, the disc type determination unit 27 determines, for example, whether the optical disc D is a single-layer or dual-layer optical disc.

Fig. 13 shows a schematic configuration of an optical disc device according to another example of the present invention. The optical disc device in FIG. 13 is different from the optical disc device in FIG. 12 in that the optical disc in FIG. 13 does not include the disc type determination unit 27 which the optical disc device in FIG. 12 includes. The rest of the basic configuration of the optical disc device in FIG. 13 is the same as that of the optical disc device in FIG. 12 .

Next, the signal processing circuit 24 will be described in detail. The signal processing circuit 24 performs the following operations.

FIG. 1 is a block diagram showing an example of a schematic configuration of the signal processing circuit 24 according to the first embodiment. The signal processing circuit 24 in the first embodiment corresponds to the signal processing circuit 24 of the optical disc device shown in FIG. 12 . The signal processing circuit 24 in the first embodiment includes an analog-to-digital converter (ADC) 41 , an offset controller 42 , a subtractor 43 , an equalizer 44 , and a Viterbi decoder 45 .

The analog reproduced signal output from the photodetector 17 is amplified by a preamplifier (not shown), and then converted into a digital reproduced signal by the ADC 41. The offset controller 42 outputs an offset signal representing the amount of offset. The subtracter 43 subtracts the offset signal (offset amount) from the digital reproduced signal. The subtraction result is input to the equalizer 44 . The equalizer 44 adjusts the frequency characteristic and phase characteristic of the reproduced signal. Thus, the output signal (hereinafter referred to as an equalized signal) acquires a partial response characteristic (hereinafter referred to as a PR characteristic). The Viterbi decoder 45 discriminates the signal from the equalized signal according to the Viterbi algorithm, and outputs a binary signal.

The equalized signal and the binary signal are input to an offset controller 42, and the offset controller 42 calculates an offset. The offset controller 42 also receives a parameter selection signal. Data representing the type of the disc is recorded at a predetermined position on the disc D in advance. The disc type determining unit 27 of the optical disc device determines the disc type based on the information indicating the disc type included in the reproduced data. A parameter selection signal according to the disc type is sent to the offset controller 42 .

The block diagram of FIG. 2 shows a schematic configuration of the offset controller 42 . The offset controller 42 includes a path calculator 51 , a subtractor 52 , an integrator 53 , a multiplier 54 , a memory 55 , and a selector 56 .

The path calculator 51 calculates a path corresponding to the PR characteristic to be used from the binary signal. Subtractor 52 subtracts the equalized signal from this path. The result of this subtraction is the error signal. The error signal is input to an integrator 53 . The integrator 53 includes an adder 531 and a unit delay element 532 . The multiplier 54 multiplies the output signal from the integrator 53 by a gain. The multiplication result is an offset signal. The memory 55 stores in advance gains (parameters) corresponding to the types of discs. For example, a single-layer disc has a gain of 1/2048, and a dual-layer disc has a gain of 1/512. These gains correspond to control bands of 5 and 20 kHz in the offset controller 42, respectively. The selector 56 selects the gain of the single-layer or dual-layer optical disc according to the parameter selection signal.

3 to 6 are used to explain the effects obtained by the signal processing circuit 24 according to the first embodiment.

Fig. 3 shows reproduced signals obtained from a single-layer optical disc in the case where the above-mentioned offset control is not applied. Fig. 4 shows a reproduced signal obtained from a single-layer optical disc in the case where the above-described offset control is applied. As is apparent from FIGS. 3 and 4, the reproduced signal obtained from the single-layer optical disc exhibits less fluctuation in offset. That is, even when the control frequency band (signal processing bandwidth) of the offset controller 42 is 5 kHz, offset fluctuation can be sufficiently suppressed.

Fig. 5 shows reproduced signals obtained from a dual-layer optical disc in the case where the above-mentioned offset control is not applied. Fig. 6 shows reproduced signals obtained from a dual-layer optical disc in the case where the above-described offset control is applied. The offset fluctuation of a reproduced signal obtained from a dual-layer disc is larger than that of a reproduced signal obtained from a single-layer disc. Also, the fluctuation frequency of the reproduced signal from the dual-layer disc is higher than that of the reproduced signal from the single-layer disc. As shown in FIG. 6 , when the control band (signal processing bandwidth) of the offset controller 42 is set to 20 kHz, offset fluctuation can be suppressed.

The flowchart of Fig. 14 briefly shows the signal processing of the first embodiment. As shown in FIG. 14, the photodetector 17 of the optical disc device shown in FIG. 12 detects reflected light from the optical disc (ST11). Based on the information indicating the type of the optical disc reflected in the reflected light, the disc type determining unit 27 of the optical disc device shown in FIG. 12 also determines the type of the optical disc (ST12). Also, based on the determination result (parameter selection signal) of the optical disc type, the offset controller 42 of the signal processing circuit 24 in the optical disc device as shown in FIG. (ST13). Furthermore, based on the selected parameters, the signal processing circuit 24 performs subtraction and the like, and finally generates a binary signal (ST14).

As described above, the optical disc device of the present invention is capable of changing the control band (signal processing bandwidth) of the offset controller according to the type of disc. Therefore, data can be reproduced from various optical discs with sufficient recognition performance.

FIG. 7 is a block diagram showing a schematic configuration of a signal processing circuit 24 according to the second embodiment. The signal processing circuit 24 in the second embodiment corresponds to the signal processing circuit 24 of the optical disc device shown in FIG. 13 . The signal processing circuit 24 in the second embodiment includes an ADC 41, an offset controller 42, a subtractor 43, an equalizer 44, a Viterbi decoder 45, an SbER calculator 46 and a controller 47.

The analog reproduced signal output from the optical disc 17 is amplified by a preamplifier (not shown), and then converted into a digital reproduced signal by the ADC 41. The offset controller 42 outputs an offset signal representing the amount of offset. The subtracter 43 subtracts the offset signal (offset amount) from the digital reproduced signal. The subtraction result is input to the equalizer 44 . The equalizer 44 adjusts the frequency characteristic and phase characteristic of the reproduced signal. Thus, the equalized signal from the equalizer 44 acts as a PR characteristic. The Viterbi decoder 45 discriminates the signal from the equalized signal according to the Viterbi algorithm, and outputs a binary signal.

The equalized signal and the binary signal are input to an offset controller 42, and the offset controller 42 calculates an offset. The offset controller 42 also receives the parameter selection signal. The configuration of the offset controller 42 is shown in FIG. 2 . It should be noted that it is assumed that nine gains are stored in the memory 55 in the second embodiment, whereas two gains are stored in the memory 55 in the first embodiment. That is, the memory 55 stores nine types of gains, namely, 1/32, 1/64, 1/128, 1/256, 1/512, 1/1024, 1/2048, 1/4096, and 1/8192 . These gains correspond to the control frequency bands (signal processing bandwidth) of 320, 160, 80, 40, 20, 10, 5, 2.5, and 1.3 kHz in the offset controller 42, respectively.

The SbER calculator 46 calculates an SbER value representing the quality of the reproduced signal. The SbER value is an estimated value of the bit error rate (hereinafter referred to as bER). The method of calculating this SbER value is described in Jpn.J.Appl.Phys.Vol.42(2003) pp.971-975. The SbER value is sent to the controller 47 . The controller 47 measures the relationship between the parameter selection signal from the disc type determination unit 27 and the SbER value, and then outputs the parameter selection signal so that an appropriate SbER value can be finally obtained.

8 and 9 are used to explain the effect of the signal processing circuit 24 according to the second embodiment.

FIG. 8 shows the relationship between the offset control band (signal processing bandwidth) and the SbER value on a single-layer optical disk. As shown in FIG. 8, on a single-layer optical disc, when the offset control band is 80 kHz or less, the SbER value fluctuates little. Therefore, the controller 47 finally outputs a parameter selection signal corresponding to one of the 80, 40, 20, 10, 5, 2.5, and 1.3 kHz offset control frequency bands.

Fig. 9 shows the relationship between the offset control band and the SbER value on a dual-layer disc. As shown in FIG. 9, on a dual-layer optical disk, a preferable SbER value can be obtained when the offset control band is 10 to 80 kHz. Therefore, the controller 47 finally outputs a parameter selection signal corresponding to one of the 80, 40, 20, and 10 kHz offset control frequency bands.

Fig. 15 is a flowchart schematically showing the signal processing of the second embodiment. As shown in FIG. 15, the photodetector 17 in the optical disc device shown in FIG. 13 detects reflected light from the optical disc (ST21). Also, the offset controller 42 of the signal processing circuit 24 in the optical disk device as shown in FIG. (ST22). Also based on the selected parameters, the signal processing circuit 24 performs subtraction and the like, and finally generates a binary signal (ST24).

As described above, in the present invention, the offset control band (signal processing bandwidth) can be changed so that preferable re-signal quality is obtained. Therefore, sufficient recognition performance can be obtained regardless of the type and characteristics of the optical disc.

In the second embodiment described above, the SbER value was used to measure the quality of the re-signal. However, the present invention is not limited thereto. Another measurement method can also be used.

As described above, the optical disc device of the present invention can adjust the control band (signal processing bandwidth) of the offset controller 42 according to the reproduction signal of the optical disc. Therefore, sufficient performance can be obtained even when the offset fluctuation frequency of the reproduced signal from the optical disc varies.

FIG. 10 shows a schematic configuration of a signal processing circuit 24 according to the third embodiment. The signal processing circuit 24 of the third embodiment can be used as the signal processing circuit 24 of the optical disc shown in FIG. 12 . In the first and second embodiments, the optical disc apparatus changes the control band of the offset controller 42 in digital signal processing. In the third embodiment, the optical disc device changes the offset control bandwidth in analog signal processing.

The signal processing circuit 24 of the third embodiment includes a high-pass filter (HPF) 40 , an ADC 41 , an equalizer 44 , a Viterbi decoder 45 , and a parameter controller 48 . The HPF 40 removes low-frequency components and reproduces high-frequency components in the signal by analog. The signal processing circuit 24 of the third embodiment uses the HPF 40 as an offset control unit. That is, the signal processing circuit 24 of the third embodiment is greatly different from that of the first embodiment in that, in the third embodiment, the signal processing circuit 24 uses the HPF 40.

Note that the HPF 40 can also be applied to the signal processing circuit 24 of the second embodiment. That is, the signal processing circuit 24 of the third embodiment can be used as the signal processing circuit 24 of the optical disc apparatus shown in FIG. 13 .

Based on the parameter selection signal supplied by the disc type determination unit 27, the parameter controller 48 controls the parameters of the HPF 40. That is, based on the parameter selection signal, the parameter controller 48 sets predetermined parameters of the HPF 40, and controls the filter characteristic (signal processing bandwidth) of the HPF 40. Therefore, the HPF 40 performs filtering based on filtering characteristics corresponding to a single-layer or double-layer disc.

FIG. 11 shows a schematic configuration of a signal processing circuit 24 according to the fourth embodiment. The signal processing circuit 24 of the fourth embodiment can be used as the signal processing circuit 24 of the optical disk shown in FIG. 12 . In the first to third embodiments, the optical disc device changes the offset control band or the HPF parameter according to the type and characteristics of the optical disc. In the fourth embodiment, the optical disc device changes the gain control band (signal processing bandwidth) according to the type and characteristics of the optical disc.

The signal processing circuit of the fourth embodiment includes an ADC 41, an offset controller 42, a subtractor 43, an equalizer 44, a Viterbi decoder 45, a parameter controller 48, and an automatic gain control (AGC) 49. The signal processing circuit 24 of the fourth embodiment uses the AGC 49 as a gain control unit. That is, the signal processing circuit 24 of the fourth embodiment is greatly different from that of the third embodiment in that, in the fourth embodiment, the signal processing circuit 24 uses the AGC 49. Also, AGC 49 may be an analog AGC or a digital AGC.

In addition, an AGC 49 can also be used as the signal processing circuit 24 of the second embodiment. That is, the signal processing circuit 24 of the fourth embodiment can be used as the signal processing circuit 24 of the optical disc device shown in FIG. 13 .

The parameter controller 48 controls parameters of the AGC 49 based on the parameter selection signal supplied from the disc type determination unit 27. That is, the parameter controller 48 controls the gain control band (signal processing bandwidth) of the AGC 49 by switching between parameters for a single-layer disc and parameters for a dual-layer disc.

As described above, in the present invention, the following functional effects can be obtained.

1. Since the offset control band (signal processing bandwidth) can be adjusted according to the type of optical disc, optimal reproduction of information can be achieved regardless of the type of optical disc.

2. Since the offset control band (signal processing bandwidth) can be adjusted according to the disc type and the characteristics of the reproduced signal, optimal reproduction of information can be realized regardless of the disc type and the characteristic difference of the reproduced signal.

3. Since the gain control band (signal processing bandwidth) can be adjusted according to the type of optical disc, it is possible to achieve optimal reproduction of information regardless of the type of optical disc.

4. Since the gain control band (signal processing bandwidth) can be adjusted according to the type of disc and the characteristics of the reproduced signal, optimal reproduction of information can be realized regardless of the difference in the type of disc and the characteristic of the reproduced signal.

Additional advantages and modifications will also readily occur to those skilled in the art. Therefore, the invention in its broadest sense is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit and scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims (9)

1. one kind based on reappearing the optical disc apparatus of the information on the CD from the reflected light of CD, it is characterized in that comprising:

Detecting unit (10) is provided for detecting the reflected light from CD;

Signal processing unit (24) is provided for by generating binary signal based on catoptrical simulation reproducing signal; With

Determining unit (27) is provided for determining the type of CD based on the information of expression optical disc types that the information of expression optical disc types is reflected in the reflected light,

Wherein, signal processing unit is selected one of them based on definite result of optical disc types from a plurality of parameters that are used for definite signal Processing bandwidth, and based on selected parameter, generates binary signal from the simulation reproducing signal.

2. according to the device of claim 1, it is characterized in that:

Determining unit determines that based on the information of expression optical disc types CD is any in single-layer optical disc and the double-layer CD, and

Signal processing unit is based on definite result of optical disc types, one of them corresponding parameter of selection and single-layer optical disc and double-layer CD from a plurality of parameters, and generate binary signal from the simulation reproducing signal based on selected parameter.

3. according to the device of claim 1, it is characterized in that signal processing unit comprises:

Converting unit (41) is provided for converting the simulation reproducing signal to the digital reconstruction signal,

Subtrator (43) is provided for deducting side-play amount from the digital reconstruction signal,

Balanced unit (44) is provided for based on generating equalizing signal by deducting the digital reconstruction signal that side-play amount obtains,

Binary cell (45) is provided for generating binary signal from balanced unit, and

Offset control unit (42) be provided for selecting one of them based on definite result of optical disc types from a plurality of parameters, and based on selected parameter, equalizing signal and binary signal is controlled side-play amount.

4. according to the device of claim 1, it is characterized in that signal processing unit comprises:

Filter unit (40) is provided for removing low-frequency component, and by the radio-frequency component in the simulation reproducing signal,

Converting unit (41), the simulation reproducing signal that is provided for therefrom removing low-frequency component converts the digital reconstruction signal to,

Balanced unit (44) is provided for generating equalizing signal based on the digital reconstruction signal,

Binary cell (45) is provided for generating binary signal from equalizing signal, and

Parameter selection unit (48) is provided for the definite result based on optical disc types, from being used for selecting one of them by a plurality of parameters of filter unit control filtering characteristic.

5. according to the device of claim 1, it is characterized in that signal processing unit comprises:

Gain control unit (49) is provided for controlling the gain of simulation reproducing signal,

Converting unit (41) is provided for converting the controlled simulation reproducing signal of its gain to the digital reconstruction signal,

Subtrator (43) is provided for deducting side-play amount from the digital reconstruction signal,

Balanced unit (44) is provided for based on generating equalizing signal by deducting the digital reconstruction signal that side-play amount obtains,

Binary cell (45) is provided for generating binary signal from equalizing signal,

Offset control unit (42) is provided for based on equalizing signal and binary signal side-play amount being controlled, and

Parameter selection unit (48) is provided for the definite result based on optical disc types, from being used for selecting one of them by a plurality of parameters that gain control unit is controlled the gain control frequency band.

6. one kind based on reappearing the optical disc apparatus of the information on the CD from the reflected light of CD, it is characterized in that comprising:

Detecting unit (10) is provided for detecting the reflected light from CD; With

Signal processing unit (24) is provided for by generating binary signal based on catoptrical simulation reproducing signal,

Wherein, signal processing unit is based on the signal quality grade by the simulation digital reconstruction signal that reproducing signal generated, select one of them from a plurality of parameters that are used for definite signal Processing bandwidth, and, generate binary signal from the simulation reproducing signal based on selected parameter.

7. according to the device of claim 6, it is characterized in that signal processing unit comprises:

Converting unit (41) is provided for converting the simulation reproducing signal to the digital reconstruction signal,

Subtrator (43) is provided for deducting side-play amount from the digital reconstruction signal,

Balanced unit (44) is provided for based on generating equalizing signal by deducting the digital reconstruction signal that side-play amount obtains,

Binary cell (45) is provided for generating binary signal from balanced unit,

Computing unit (46) is provided for calculating the signal quality grade of equalizing signal, and

Offset control unit (42) be provided for selecting one of them based on the signal quality grade of equalizing signal from a plurality of parameters, and based on selected parameter, equalizing signal and binary signal is controlled side-play amount.

8. one kind based on reappearing the information playback method of the information on the CD from the reflected light of CD, it is characterized in that comprising:

Detect (ST11) reflected light from CD;

Information based on the expression optical disc types is determined the type of (ST12) CD, and the information of expression optical disc types is reflected in the reflected light;

Based on definite result of optical disc types, from a plurality of parameters that are used for determining the signal Processing bandwidth select (ST13) one of them; And

Based on selected parameter, by generating (ST14) binary signal based on catoptrical simulation reproducing signal.

9. one kind based on reappearing the information playback method of the information on the CD from the reflected light of CD, it is characterized in that comprising:

Detect (ST21) reflected light from CD;

Based on the signal quality grade of digital reconstruction signal, from a plurality of parameters that are used for determining the signal Processing bandwidth select (ST22) one of them, wherein, described digital reconstruction signal is by generating based on catoptrical simulation reproducing signal; And

Based on selected parameter, generate (ST23) binary signal by the simulation reproducing signal.

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